Lubricants

ABSTRACT

The addition of a small amount of an alkyl sulfenyl N,N-dialkyl dithiocarbamate to lubricating oils, gear oils, greases, and the like improves the various properties thereof including the higher pressure properties, the stability of the so-treated lubricants against oxidation and rust, as well as antiwear properties, antiscuffing properties, and the like.

1U mted States Fateat 11 1 1111 3353,7775

Williams 1 1 Dee. 10, 1197 1 LUBRICANTS 2,719,125 9/1955 RObeIIS 252/472,812,306 11/1957 Liehe 252/421 [75] Inventor Ralph Wlllmms, Bartlesvlle2,963,433 12/1960 Little et al. 252/47 Okla- 3,112,270 11/1963 Mitaceket al... 252/41 Assigneez Eetroleum p y 3,481,871 Myers Ct al. X

Bartlesville, Okla.

[22] Filed; 159 1973 Primary ExaminerH. Sneed [21] Appl. No.: 332,566

Related U.S. Application Data Continuation-impart of Ser. No. 123,111,March 10, 1971, abandoned.

US. Cl 252/42.l, 252/47, 252/402 Int. Cl. C10m 1/36, C10m 1/38 Field ofSearch 252/42.1, 47

References Cited UNITED STATES PATENTS 3/1945 Ross et al. 252/47ABSTRACT 10 Claims, N0 Drawings LUBRICANTS This is acontinuation-in-part application of application Ser. No. 123,111, filedMar. 10, 1971, entitled Lubricants, now abandoned.

This invention relates to improved lubricants and processes of preparingthe same. In accordance with another aspect, this invention relates toaddition agents imparting to lubricants increased stability towardoxidation and rust as well as improved high pressure characteristics. Inaccordance with a further aspect, this invention relates to lubricatingoils and greases having improved physical characteristics havingincorporated therein a small quantity of an alkyl sulfenyl N,N-dialkyldithiocarbamate, also referred to as alkyl sulfenyl dialkyldithiocarbamate in this application. In accordance with a still furtheraspect, this invention relates to lubricant additives exhibitingantiwear and antiscuffing properties. In accordance with another aspect,this invention relates to improving the physical properties oflubricants by the addition thereto of crude or unrefined alkyl sulfenyldialkyl dithiocarbamates.

Various efforts have been made with respect to improving the physicalcharacteristics of lubricating oils and greases. One problem oftenencountered with lubricants is the high pressure characteristics as wellas the antiwear and antiscuffing properties. Also, many lubricants donot exhibit a satisfactory stability toward oxidation and rust. Inaccordance with the invention, it has been found that addition of alkylsulfenyl dialkyl dithiocarbamates to lubricants substantially improvesthe lubricants with respect to the high pressure characteristics as wellas oxidation, rust, antiwear, antiscuffing, and other properties of thelubricants.

Accordingly, an object of this invention is to provide improvedlubricating oils and greases.

A further object of this invention is to provide lubricating oils andgreases improved in high pressure or extreme pressure characteristics.

A further object of this invention is to provide lubricating oils andgreases having increased stability toward oxidation and rust.

Another object of this invention is to provide effective antiwear andantiscuffing additives for lubricants.

Other objects and aspects, as well as the several advantages of theinvention, will be apparent to those skilled in the art upon reading thespecification and the appended claims.

In accordance with the invention, lubricating oils and greases areimproved in physical properties by the addition of a small effectiveamount of at least one alkyl sulfenyl dialkyl dithiocarbamate.

It has been found that alkyl sulfenyl dialkyl dithiocarbamates functionas rust inhibitors, antioxidants, antiwear additives and antiscuffingadditives in lubricating oils and greases. Additionally, it has beenfound that lubricating oils and greases containing a small quantity ofat least one alkyl sulfenyl dialkyl dithiocarbamate exhibit excellentcharacteristics as extreme pressure lubricants.

In accordance with one specific embodiment of the invention, lubricatingoils and grease formulations are improved in the above characteristicsby the addition of t-butylsulfenyl N,N-dimethyldithiocarbamate,toctylsulfenyl N,N-dimethyldithiocarbamate, tnonylsulfenylN,Ndimethyldithiocarbamate, and tdodecylsulfenylN,N-dimethyldithiocarbamate. The toctyl, t-nonyl and t-dodecylmercaptans from which these sulfenyl compounds are made, are productsfrom the reaction of i-butene dimer, propylene trimer and tetramer,respectively, with hydrogen sulfide and are mixtures of isomers. Theseisomeric thiols are used to prepare the sulfenyl chloride intermediatesfor the preparation of the alkyl sulfenyl N,N-dialkyldithiocarbamates ofthis invention. Hereinafter, these compounds will be referred to astertiary or t-compounds, it being understood that they include isomericspecies. The names have found acceptance in the chemical industry.

The alkyl sulfenyl dialkyl dithiocarbamates that can be employedaccording to this invention are represented by the formula RSSC(S)N(R')wherein R is a straight or branched chain alkyl radical having up to 14carbon atoms and generally from 1 to 10 carbon atoms and R is a straightor branched chain alkyl radical having from I to 5 carbon atoms, andfurther wherein R and R can be the same or different.

Examples of compounds which can be used include: t-butylsulfenylN,N-dimethyldithiocarbamate, methylsulfenyl N,N-dimethyldithiocarbamate,ethyl-sulfenyl N,N-diisobutyldithiocarbamate, octylsulfenylN,N-diethyldithiocarbamate, t-octylsulfenyl N,N-dimethyldithiocarbamate,2,2-(dimethyl)octylsulfenyl N-methyl-N-ethyldithiocarbamate,2,3-(dimethyl)hexylsulfenyl N,N-diisoamyldithiocarbamate,t-nonylsulfenyl N,N-dimethyldithiocarbamate, t-dodecylsulfenylN,N-dimethyldithiocarbamate, tetradecylsulfenylN,N-dimethyldithiocarbamate, ttetradecylsulfenylN,N-dipentyldithiocarbamate, and the like. If desired, mixtures of theabove compounds can be used. Also, if desired pure as well as crude orunrefined compounds, or mixtures thereof, can be used.

The alkyl sulfenyl dialkyl dithiocarbamates that can be employedaccording to the invention are well known in the art and can be preparedaccording to any known procedure.

The amount of alkyl sulfenyl dialkyl dithiocarbamate incorporated intothe lubricants according to the invention is a finite amount sufficientto improve the physical properties of the lubricants and is ordinarilyat least about 0.05 weight percent and can range from 0.1 to 5 weightpercent, preferably from 0.5 to 2 weight percent.

In the preparation of the lubricating compositions, various mineral oilsare employed. Generally, these are of petroleum origin and are complexmixtures of many hydrocarbon compounds. Preferably the mineral oils arerefined products such as are obtained by wellknown refining processessuch as by hydrogenation, polymerization, dewaxing, etc. Frequently, theoils have a Saybolt viscosity at F in the range of about 60 to 5,000 anda Saybolt viscosity at 210F of about 30 to 250. The oils can be ofparaffinic, naphthenic or aromatic types, as well as mixtures thereof.The additives of the invention have special advantages when employedwith paraffinic types of oil such as are obtained by solvent extractionof a suitable refinery stream. Many suitable compositions are availableas commercial products such as those used as motor oils, fuel oils,automatic transmission oils, gear oils, and the like. The invention isapplicable to any lubricating oils having a problem with respect to theviscosity when subjected to high temperature conditions for long periodsof time.

Generally, any conventional and commercially available grease isamenable to this invention. The grease employed can have been thickenedin any known manner such as by the use of soaps and/or by dissolvingpolymers in the oil at temperature of at least 245F and the like.

Suitable greases include substantially any grade of fiowable grease asdefined by the National Lubricating Grease Institute (NLGI). Forexample, NLGI grade greases from 000 to 6 can be employed in thisinvention. Also, greases having an ASTM D 217-68 penetration at 60strokes in the range of 85 to 475 can be employed.

The lubricating oil bases which can be employed to make greases of thisinvention can be mineral, vegetable, or animal in nature, preferablelubricant bases having at least a major amount of mineral origin. Suchoils include refined oils having a viscosity of from about 35 to about240 SUS at 210F. White mineral oil as well as other specialty oils canbe used and are among the preferred oils.

Thickeners for the oils can be employed in amounts up to weight percentof the oil. Various soaps normally used to thicken greases can be usedand they include metal salts of high molecular weight acids, forexample, acids of 10 to 30 and preferably 16 to 24 carbon atoms, eithersynthetic or of animal or vegetable origin. Other carboxylic acidsuseful for making soaps of metal salts include those derived fromtallows, hydrogenated fish oil, castor oil, wool grease, and rosin.Generally, the alkali metal or alkaline earth metal or aluminum or leadsalts of acids such as lauric, palmitic, oleic, stearic, and the likeare used. One of the preferred soaps is the lithium soap ofl2-hydroxystearic acid. While soaps of a general nature can be used inthe greases of this invention, it should be understood that theinvention is of use with soapless greases formed essentially frompolymers and oil alone, with or without small amounts of known greaseadditives such as fillers and the like. Thus, polymers such aspolyethylene and polypropylene can be employed as thickeners, together,alone or in conjunction with other thickeners such as soap.

Other materials normally used in greases can also be employed in thegreases applicable to this invention. For example, additives such asrust inhibitors, antioxidants, fillers, pigments, perfumes, and the likecan be employed. Some examples of such materials includepropylenediamine, phenyl-a-naphthylamine, phenothiazine, mica, asbestos,powdered lead, powdered zinc, talc, alumina, titanium dioxide,molybdenum disulfide, bentones, carbon black, nitrobenzene, and thelike. Generally, the amount of these modifiers is less than about 10percent of the total weight of the grease.

Other agents than those which have been mentioned can be present in thelubricant composition such as dyes, pour point depressants, heatthickened fatty oils, sulfurized fatty oils, sludge dispersers,thickeners, viscosity index improvers, oiliness agents, resins, rubber,and the like.

The additives of the invention can also be used in other mineral oilproducts such as motor fuels, heating oils, hydraulic fluids, torqueconverter fluids, cutting oils, flushing oils, turbine oils, transformeroils, industrial oils, process oils, and the like, and generally asantioxidants and rust inhibitors in mineral oil products.

EXAMPLE I The extreme pressure effectiveness of an additive according tothe invention was compared with known additives in a lubricating oilstock. As set forth in Table 1 below, one percent of t-butylsulfenylN,N-dimethyldithiocarbamate, an additive of the invention, wasincorporated into a lubricating oil stock and compared with three knownadditives, all of which were present at one percent concentration, andthe formulations were subjected to a 4-ball wear test (ASTM D 2956-67T).

TABLE I Load Wear Lubricant Additive to Weld, Kg Scar, M

l% t-butylsulfenyl N,N-dimethyldithiocarbamate 200 2505 1% Anglamol-2289 l% Lubrizol 1395 l20 l% Vanlube 71 None 1 l0 3750 Added to KansasCity l0 lube oil stock.

" Zinc dialkyl dithiophosphate: P, 6.8%; S, l4.27 Zn, 7.27:. Zincdialkyl dithiophsophatc: P, 9.5%; S, 20.0%; Zn, l071.. Lead diamyldithiocarbamate.

Commercial additives Supplied in oil carriers, concentration of activeingredients unknown.

As can be seen from above, the additive of the invention exhibitedsubstantial improvement in the extreme pressure effectiveness ascompared with the values exhibited by the known additives.

EXAMPLE ll An antioxidant test was carried out comparing an additive ofthe invention with a known antioxidant. A lubricating oil (a 10W30 motoroil with detergents, dispersants and viscosity improvers, but containingno antioxidant) was formulated to contain either 1 percentt-butylsulfenyl N,N-dimethyldithiocarbamate, an additive of theinvention, or to contain a known additive in 1 percent concentration,and each was evaluated for oxidation inhibition, in accordance with ASTMD 942.

As can be seen from the above data, the additive of the inventionexhibits better oxidation inhibition than with the known antioxidant.

EXAMPLE III A grease formulation was formulated by milling into thesemifinished grease O.53% t-butylsulfenyl N,N-dimethyldithiocarbamate.For comparison, one formulation was prepared to contain 2 /2% by weightof Vanlube 71.

The basic grease was a lithium soap base grease containing 4 percent byweight high density polyethylene. Results are tabulated below.

Timken OK Load, lbs.

Grease (control, no additive) specification l0 Grease plus 2/% Vanlube71 (lead diamyldithiocarbamate) 7075 Grease plus 0.5% tert-butylsulfenylN,N

dimethyldithiocarbamate 30 fail Grease plus 1.0% do. 50 pass Grease plus2.0% do. 50 do. Grease plus 3.0% do. 50 do.

Due to the desire to eliminate heavy metals, like lead, from theenvironment, substitution of a non-metallic additive may be required andthe present invention provides an alternative non-metallic antioxidantwhich meets current specification (50 minimum) at 1 weight percent andhigher additive levels.

EXAMPLE IV A number of alkylsulfenyl dialkyldithiocarbamates wereprepared and the crude products resulting were evaluated in lubricantcompositions. The preparation of these materials are set forth below.

Typical Syntheses of t-alkylsulfenyl N,N-dimethyldithiocarbamatest-Butyl Materials t-Butylmercaptan 180 g n-Heptane 1800 ml Chlorine 136g 40% aqueous sodium N.N-dimethyldithiocarbamate 715 g A solution oft-butyl mercaptan in n-heptane and gaseous chlorine were metered inseparate streams to a glass mixing tee where they converged inapproximately stoichiometric quantities and then passed into a steamjacketed 3-liter, 3-necked flask where the mixture was continuallyrefluxed to remove HCl. The time required for introducing the reactantswas 121 minutes. When the mercaptan-chlorine reaction step formingt-butylsulfenyl chloride had been completed, aqueous sodiumN,N-dimethyldithiocarbamate solution was added rapidly with briskstirring to the resulting tertbutylsulfenyl chloride solution in the3-necked flask, and the mixture was stirred for about minutes. Thephases were separated, and the organic phase was washed twice withwater. Then the heptane was stripped from the organic phase leaving 381grams (91.1 percent crude yield) of yellow oil. A portion of the product(50 g) was recrystallized from 200 ml hheptane, yielding 46.6 g ofcrystalline product which corresponded to a 93.3 percent purity for thecrude product. The remaining 331 grams of crude product was dissolved insufficient xylene to give 1,103.3 grams of total solution containing 30weight percent tbutylsulfenyl N,N-dimethyldithiocarbamate.

t-Octyl Materials t-Octyl mercaptan 146 g n-Heptane 800 ml Sulfurylchloride ($0 0 g 40% aqueous sodium N,N-dimethyldithiocarbamate 357.5 g

Sulfuryl chloride was added to t-octyl mercaptan in nheptane in areaction flask over a 10-minute period to form the sulfenyl chloride.The solution was heated to 85C to drive off S0 and HCll, then was washedwith water. Aqueous sodium N,N-dimethyldithiocarbamate was then addedrapidly to the sulfenyl chloride solution with stirring. After stirringfor 15 minutes, the phases were separated and the organic phase waswashed with water. Then the heptane was stripped from the organic phaseunder vacuum in a rotary evaporator on a steam bath. The crudet-octylsulfenyl N,N-dimethyldithiocarbamate weighed 223.0 g (84.2percent yield).

Analysis Calculated Found C 49.7 49.54 H 8.7 7.65 N 5.3 4.65 S 36.2 37.l

t-Nonyl Materials t-Nonyl mercaptan n-Heptane Chlorine 40% Aqueoussodium N,N-dimethyldithiocarbamate Analysis Calculated Found C 5 1 .5554.8 H 9.03 9.9 N S .01 4.2 S 34.40 30.4

t-Dodecyl Materials T-Dodecyl mercaptan n-Heptane Chlorine 40% AqueousSodium N,N-dimethyldithiocarbamate 449 g t-dodecyl mercaptan wasdissolved in sufficient n-heptane to make 2,000 ml of solution. 1,800 mlof this solution was used to prepare the desired product using gchlorine and 715 g 40% aqueous sodium N,N-dimethyldithiocarbamate.

Synthesis was carried out in same manner as that for the butylderivative. The yield of crude tdodecylsulfenylN,N-dimethyldithiocarbamate product was 528 g (82.2 percent).

Analysis Calculated Found (I 56.01 00.54 H 3.73 10.52 N 4.36 3.27 S29.90 25.7

EXAMPLE V The extreme pressure effectiveness (ASTM Method D-2509-68) ofthe crude products produced in Example IV was compared with a knownadditive in a grease formulation. The results of these evaluations areset forth below.

TABLE 111 Test Conditions: Timken Machine, 10-minu Grease Base Stock:Philube* L-2 (Lithium Base) tes running time at 800 rpm.

Three of the compounds tested at the 1% level meet the currentspecification value of 50 lbs. minimum and would therefor be acceptableashless additives to replace ingredients containing heavy metals such aslead and zinc. The other compound, t-dodecylsull'enylN,N-dimethy1dithiocarbamate showed sufficient improvement over thecontrol to be considered an effective additive.

EXAMPLE VI Wear tests were conducted using high purity and crudeproducts of this invention in a lubricating composition for a sequence Iengine test. The results are given below.

Minimum acceptable OK load, 50 1b.

OK load: Test block scar with straight line sides and no metal pickup.

Critical OK Load: Test block scar metal pickup Failure Load: est blockscar with metal of scar pattern to be irregular.

with straight line sides but with pickup causing boundary lines t-C,derivative worked equally well over 1-3 weight percent concentrationrange whether used in high purity or crude form, or as a solution in xlene (solution charged to provide 1-3'71 t-butylsulfenyl N.N-dimetyldithiocarbamate).

Crude t-octyl derivative.

Crude t-nonyl derivative. Crude t-dodecyl derivative. Phillips PetroleumCompany trademark.

TABLE IV SEQUENCE 1 TEST "CAMSHAFT AND VALVE LIFTER WEAR t-AlkylsulfenylN,N-dimethyldithiocarbamates Test Conditions:

1967 Ninety-Eight Olds en inc.

2500 rpm mph) Lig t Load Road Load.

Coolant temperature, 94F. Oil Temperature, F (max.)

Engine operates for 10 minutes, then is shut down for 50 minutes of eachhour for 30 hours. Running time approximates 325 miles.

Test Oil: Trop-Arctic (Phill motor oil, SAE 1OW-3 ips; Petroleum Companytrademark) all season 0 without antiwear agent Fuel: Kansas Citypipeline base with 3 cc TEL/gal.

Camshaft Lobe Wear, Valve Lifter"" 1n."" Footcrown Wear. In. Base OilPlus Antiwear Additive Min. Max. Avg. Min. Avg.

None .0006 .1994 .0868 .0000 .0620 .0189 0.19 Wt. Lubrizo1-1395 .0012.0005 .0000 .0000 .0000

0.5 Wt.% t-Butylsultenyl DMDTC* .0016 .0003 .0000 .0010 .0001

0.05 Wt.% do. .0000 .0012 .0004 .0000 .0020 .0014 0.03 Wt.% do. w .0000.0021 .0003 .0000 .0020 .0010 0.05 Wt.% do. .0000 .0004 .0002 .0000.0010 .0003 0.5 Wt.% t-Octylsulfenyl do. .0000 .0004 .0001 .0000 .0010.0003

"N,N'dimethyldithiocarhamatc.

"" The method sets no wear specs, says only that wear should not beexcessive. Commercial product: hydrocarbon solution of zinc dialkyldithiophosphate. t-Butylsull'enyl N.N-dimethyldithiocurhamatc: Highpurity crystalline product from plant inventory.

Calculated for Analysis C H N Found Carbon 40.15 40.0 Hydrogen 7.22 7.1Nitrogen 6.69 6.9 Sulfur 45.94 45.5

" used 0.17 weight percent of 30)? solution in xylene of crudet-hutylsulfcnyl N.N-dimethyldithiocarbamate; estimated purity of crudeproduct: 93.3Wtf71.

"" crude t-octylsulfenyl N,N-dimethyldithiocarbamate.

" ASTM special technical publication No. 315A. Engine Test Sequences forEvaluating Automotive Lubricants for AF] Service MS, published by AS'l'M1963 EXAMPLE Vll TABLE V quantity of alkyl sulfenyl dialkyldithiocarbamate ranges from 0.1 to 5 weight percent.

3. A composition according to claim 1 wherein said mineral lburicatingoil has been thickened with an alkali metal soap to form a greaseformulation.

4. A composition according to claim 2 wherein the alkyl sulfenyl dialkyldithiocarbamate is N,N-dimethyl t-butylsulfenyl dithiocarbamate.

5. A composition according to claim 3 wherein said grease additionallycontains polyethylene, said dithiocarbamate is N,N-dimethylt-butylsulfenyl dithiocarbamate, and the amount of said dithiocarbamateis in the range 1-5 weight percent.

6. An improved lubricating composition comprising a mineral lubricatingoil having incorporated therein at least one alkyl sulfenyl N,N-dialkyldithiocarbamate having the formula R-S-SC(S)-N(R') wherein R is an alkylradical having ll4, inclusive, carbon atoms and R is an alkyl radicalhaving l5, inclusive, carbon atoms, and wherein R and R are the same orSequence lllC Test" Test Conditions:

5 ngine. Turnpike Speed (80 mph) with 55% overload (heavy trailer).Coolant temperature. 240F; Oil Temperature, 300F. Oil: 10W-40 stock withadditive package below Additive Packa e:

0.2 wt. 7 anlube PN* (phenyl-linaphthylamine) 1.0 wt. 7! Ethyl 702*(4.4'-methylene his(2,6-di-t-butylphenol) 2.0 wt. 72 Vanlube SS*(mixture of octylated dipheny amines) 2.15 wt. V.l. improver(hydrogenated butadiene-styrene copolymer) 0.2 wt. 9? A 152 pour pointdepressant (a polymethacrylate base acryloid resin) 6.0 wt. '71 Lubrizol934 dis ersant (a mixture of 90% b succinic ester and 10 1 by wt. of amixture of polyisohutenyl y wt. polyisobutenyl succinamide and asuccinamide derived from polybutenyl succinic anhydride and alkylenepolyamincs) 10.0 ppm DC200 Silicone oi antifoam agent Camshaft LobeLifter Wear. lnchcs Ashlcss antioxidants Used 0.34 wt. Z of 307: crudet-hutylsulfenyl DMDTC solution in xylene. Crude t-nonylsulfenyl DMDTC.

ASTM special technical publication 315E Engine Oils. published by ASTM(1971).

While the samples do not meet the GM specification values it should bepointed out that these specifications were set for a metal containingadditive material, such as zinc dialkyldithiophosphate. No standardshave been set for an ashless additive. These are now in the developmentstage. At the 1% level the t-nonylsulfenyl DMDTC is very close to the GMvalues and would be considered an adequate, ashless, metal-freesubstitute for the metal containing additive.

I claim:

1. An improved lubricating composition comprising a mineral lubricatingoil having incorporated therein a small quantity of an alkyl sulfenyldialkyl dithiocarbamate having the formula RS-SC(S)N(R') wherein R is analkyl radical having l-lO, inclusive, carbon atoms and R is an alkylradical having l5, inclusive. carbon atoms and R and R are the same ordifferent. sufficient to improve the high pressure properties and toincrease the stability of the so-treated lubricating oil againstoxidation and rust.

2. A composition according to claim 1 wherein the Multicylinder TestSequences for Evaluating Automotive different in a finite amountsufficient to improve at least one of the physical properties of theresulting lubricating composition.

7. A composition according to claim 6 wherein the quantity of alkylsulfenyl dialkyl dithiocarbamate ranges from 0.05 to 5 weight percent.

8. A composition according to claim 6 wherein said mineral lubricatingoil has been thickened with an alkali metal soap to fonn a greaseformulation.

9. A composition according to claim 7 wherein the alkyl sulfenyl dialkyldithiocarbamate is N,N-dimethyl t-butylsulfenyl dithiocarbamate,t-octylsulfenyl N,N-dirnethyldithiocarbamate, t-nonylsulfenylN,N-dimethyldithiocarbamate, t-dodecylsulfenylN,N-dimethyldithiocarbamate.

10. A composition according to claim 8 wherein said dithiocarbamate isN,N-dimethyl t-butylsulfenyl dithiocarbarnate, t-octylsulfenylN,N-dimethyldithiocarbamate, t-nonylsulfenylN,N-dimethyldithiocarbamate, or t-dodecylsulfenylN,N-dimethyldithiocarbamate.

1. AN IMPROVED LUBRICATING COMPOSITION COMPRISING A MINERAL LUBRICATINGOIL HAVING INCORPORATED THEREIN A SAMLL QUANTITY OF AN ALKYL SULFENYLDIALKYL DITHIOCARBAMATE HAVING THE FORMULA R-S-S-C(S)-N(R'')2 WHEREIN RIS AN ALKYL RADICAL HAVING 1-10, INCLUSIVE, CARBON ATOMS AND R AND R''ARE RADICAL HAVING 1-5, INCLUSIVE, CARBON ATOMS AND R AND R'' ARE THESAME OR DIFFERENT, SUFFICIENT TO IMPROVE THE HIGH PRRESSURE PROPERTIESAND TO INCREASE THE STANILITY OF THE SO-TREATED LUBRICATING OIL AGAINSTOXIDATION AND RUST.
 2. A composition according to claim 1 wherein thequantity of alkyl sulfenyl dialkyl dithiocarbamate ranges from 0.1 to 5weight percent.
 3. A composition according to claim 1 wherein saidmineral lburicating oil has been thickened with an alkali metal soap toform a grease formulation.
 4. A composition according to claim 2 whereinthe alkyl sulfenyl dialkyl dithiocarbamate is N,N-dimethylt-butylsulfenyl dithiocarbamate.
 5. A composition according to claim 3wherein said grease additionally contains polyethylene, saiddithiocarbamate is N,N-dimethyl t-butylsulfenyl dithiocarbamate, and theamount of said dithiocarbamate is in the range 1-5 weight percent.
 6. Animproved lubricating composition comprising a mineral lubricating oilhaving incorporated therein at least one alkyl sulfenyl N,N-dialkyldithiocarbamate having the formula R-S-S-C(S)-N(R'')2 wherein R is analkyl radical having 1-14, inclusive, carbon atoms and R'' is an alkylradical having 1-5, inclusive, carbon atoms, and wherein R and R'' arethe same or different in a finite amount sufficient to improve at leastone of the physical properties of the resulting lubricating composition.7. A composition according to claim 6 wherein the quantity of alkylsulfenyl dialkyl dithiocarbamate ranges from 0.05 to 5 weight percent.8. A composition according to claim 6 wherein said mineral lubricatingoil has been thickened with an alkali metal soap to form a greaseformulation.
 9. A composition according to claim 7 wherein the alkylsulfenyl dialkyl dithiocarbamate is N,N-dimethyl t-butylsulfenyldithiocarbamate, t-octylsulfenyl N,N-dimethyldithiocarbamate,t-nonylsulfenyl N,N-dimethyldithiocarbamate, or t-dodecylsulfenylN,N-dimethyldithiocarbamate.
 10. A composition according to claim 8wherein said dithiocarbamate is N,N-dimethyl t-butylsulfenyldithiocarbamate, t-octylsulfenyl N,N-dimethyldithiocarbamate,t-nonylsulfenyl N,N-dimethyldithiocarbamate, or t-dodecylsulfenylN,N-dimethyldithiocarbamate.